Emitting or receiving vibration device for submarine sounding



April 11, 1933. P, A. D. MART! ET AL EMITTING OR RECEIVING VIBRATION DEVICE FOR SUBMARINE SOUNDING Filed Sept. 30, 1931 Patented Apr. 1 1, 1933 UNITED) STATES PATENT OFFICE PIERRE AUGUSTE DANIEL KARTI, OF MO NTBELIARD, AND CHARLES FREDERIC MARIE 33am AND ALBERT EHIIIE GUSTAVE NANDILLON, OF TOULON, FRANCE HITTING OR RECEIVING VIBRATION DEVICE FOR SUBKARINE SQUNDING Application filed September 30, 1931, Serial No. 568,134, and in France October 8 1930.

The proceeding of ascertaining the depth of the sea is known in which the depth is deduced from the time elapsed between the emission of a sonorous or ultrasonorous wave set u on board of the ship and the return of this wave to the ship after having undergone reflection at the bed of the sea.

In certain apparatuses, in order to set up the vibrations. an acoustic member in contact with the seawater is struck with a hard body, say a hammer, in other apparatuses an excitation of suitable kind generates mechanii cal vibrations 1n an acoustic radiator 1n contact with the sea water, (for instance, in the soundings b means of piezo-electric quartz).

A microp one is generally used for the reception, sometimes also the same device is used as well for the emission as for the reception when this device is a convertible one.

Whenit is impossible to mingle together or to place in juxtaposition the emitter and the receiver, they are generally settled very close to each other in order that the device be adapted. toascertain the depths precisely enough even when said depths are shallow ones (say a few fathoms).

It has been proposed, for the purpose of avoiding piercing the hull of the ship, to put ber and the hull. Because of that, during the emission, a great part of the energy is wasted created inside the wa in the hull and thus lost for the signal, and the same-vibrations, so dispelled in the hull, actuate too strongly the receiver which is placed, as said above, relatively near the emitter; during the rece tion, the vibrations of the hull by the sailing of the ship and by its inner life, are

strongly transmitted to the vibrating surface ceived energy.

of the receiver and disturb the reception of the alwa s very weak echo.

The s eet plates of the chamber, rather thin (between ,4 and k inch thick), are sensible to thereceived or emitted vibrations and so engross a part of the emitted orre- The height of the chambers has generally a rather large value (about twenty inches) relatively to the sonorous wave lengths used (which are about 20 inches for the sounds and two inches for the ultrasounds), consequently while receiving or emitting, inside the liquid filling the chamber arise acoustic resonance phenomena similar to those produced in an organ pipe, and said phenomena have for their effect to waste the acoustic energy and to lengthen the sonorous phenomfor emitting onreceiving sounding apparatus avoiding all the above drawbacks.

The principal feature is the following one: Between the hull and the part of the chamber wall which constitutes or sustains the vibrating surface is laid a device preventing the v1- brations to be transmitted from the one to the other. a

Said device shall be preferably constituted as follows: A deformable member, say a thick ring of soft indie-rubber shall be interposed between the lower edge of the chamber walls and the hull, the breadth of said ring and its height between the edge and. the bull being comparable in greatness (say oiwim-b as well for the one as for the'othcr) in order to be easily put out of shape by crushing.

. Because of its deformability. this ring, will withstand the passage ofthe vibrations from the chamber to the hulLor vice vcrsa, and further, it will afiord the fluid tightness of in the lower the chamber provided that said chamber is applied against the hull by a suflicient pres-v sure. Therefore it shall no more be necessary that the lower ed e of the chamber have the same form as the'diull, it should even be D05- sible to use a standard chamber the lower edgeof which should be plane, and which should suit to every ship. Moreover the chamber shall be fastened on the hull by binding means preventing the transmission of vibrations in order to avoid relapsing into the above indicated drawbacks, for instance by means'of stems of adjustable length fulcrumed by one end on the frame work of the ship and by the other end onanLother thick ring of soft india rubber shaped as the former one and lying on the upper side of the chamber.

Further the part of the chamber between the deformable joint and the vibratin sur-.

face shall be heavy enough to remain su stantially insensible to the vibrations, for instance the chamber shall be constituted by a cast iron cylinder about two hundred pounds weight with walls about four inches thick; lastlythe height of the chamber shall be small enough in reference with the wave length used to avoid any resonance phenomena inside theliquid filling said chamber; say it shall be only one fifth of the employed wave length or about four inches for an apparatus using a sound of audible frequency and onehalf of an inch for an apparatus using ultra audible frequencies.

By way of example. we have below disclosed and represented in cross section on the annexed Figures 1 and 2 two forms of execution of said chamber which can both be used for emission as well as for transmission.

' As .represented on Fig. 1 the chamber is constituted by a big cast iron bottomless cylnder 1. This cylinder sustains the vibratmg surface which shall be constituted by a rigid slab borne by a ring shaped and thinner zone 2 A soft india rubber ring-3 is partly fitted 1plane edge of the cylinder 1 and bears on t dicated above and is filled with a' liquid, generally water, by the pipe 5. In 4 is represented a transmission? device, say for the emission a hammer which striking on the vibrating surface shall start its free vibrations, or a receiving device as a microphone which shall detect the vibrations of 2 produced by the echo. ,The chamber is pressed against the hull by two stems each in two parts 11, 11' and 12, 12' with screwed ends the lengths of which can be adjusted by conphng boxes 11' 12" said stems are fulcrumed against the ship frame 13byone end and by the other against a flange 15 lying'on a soft india rubber ring 14 fitted in the upper face of the cylinder 1.

e hull of the ship. The inside 'of the chamber has the {small height as in- In the device represented by Fi 2 the to of the cylinder 1 is constituted y a thic slab strongly fastened on the cylinder 1, the acoustic emitter or receiver 9 is inside'the chamber 7 and sustained by a holder 10.

Owing to said construction the direct transmission of the vibrations between the vibrating surface 2 or 9 and the hull is prevented by the damping india rubber rmg 3. The damping india rubber ring 14 prevents in the same way the vibrations to be transmitted between the vibrating surface 2 or 9 and the ship frame by intermediary of the stems 11, 12. Moreover the mass of the chamber is such that it is substantially insensible to the vibrations. The small height of the same chamber hinders the resonance phenomena inside the liquid filling it. Notwithstanding the lower edge of. the chamber is plane shaped the device can be used on every ship without having to take in consideration the curvature of the hull which is moreover always small. in theparts where ing resilient damping devices between the ship and the chamber, both insulating and attaching means being arranged so as to prevent thevibrations to be transmitted to the vibrating surface otherwise than through the liquid.

2. In a device for submarine sounding according to claim 1, wherein the thickness of the walls of the liquid containing chamber sensible to the vibrations of the liquid in the said. chamber.

3. In a device for submarine soundin according to claim 1, wherein the height 0 the chamber, of the vibrations to be transmitted.

is so designated that the said wallsare not ,liquid containing chamber is small with respect to the wave length, in the liquid of the 4. In a device for submarine sounding according to claim 1 wherein the thickness of the walls of the liquid containing chamber are substantially equal to their height. 5. In a device for submarine soundin ac cording to claim 1, wherein the height 0 the liquid containing chamber is substantially one fifth ,of'the wave length, i'r the liquid'of the chamber, of thevibrations to be transmitted.

6. In' a device for submarine sounding according to claim 1, located against a curved ships hull, wherein the edges of the open face of the liquid containing chamber are in a plane, and wherein the resilient fluid tight ening means disposed between said hull and said edges of the chamber include a thick ring body of india rubber, fitted in part in the said edges of the chamber and having its width substantially equal to its free height,

and the attaching means comprising a thick ring body of india rubber fitted in part in the top edges of the said chamber and having its width substantially equal to its free height, and adjustable stems fulcrumed at one end to the ship frame above the said chamber and at the other end bearing upon the top india rubber ring.

7 In a device for submarine sounding according to claim 1, wherein the liquid containing chamber comprises a cast iron cylinder limited by two transverse cross-sections,

, the top end being closed, said cylinder being two hundred pounds weight, its external diameter being sixteen inches wide, its lateral walls four inches wide and big i 8, In a device for submarine sounding according to claim 1, wherein the top wall of the liquid containing chamber is in the form of a thick slab, of which a portion of reduced thickness is adapted to connect said slab to the lateral wall of the said chamber. In testimony whereof we aflix our signatures. 7

CHARLES EREDERIC MARIE BERTIN. ALBERT EMILE GUSTAVE NANDILLON. PIERRE AUGUSTE DANIEL IARTI. 

